1. Field of the Invention
The present invention relates to an image forming apparatus having a document reader openably and closably attached relative to an upper surface of an apparatus main body or a composite apparatus formed by combining two apparatuses.
2. Description of the Related Art
An image forming apparatus 100 as shown in FIGS. 7A to 7C has been conventionally known. It should be noted that, in FIGS. 7A to 7C, only essential parts as prior art to be compared with the present invention are shown by omitting unnecessary members in order to facilitate the description. Further, in FIGS. 7A to 7C, X-X directions and Y-Y directions are referred to as transverse directions and forward and backward directions, respectively, wherein −X direction is leftward direction, +X direction rightward direction, −Y direction forward direction and +Y direction backward direction.
This image forming apparatus 100 is provided with a box-shaped apparatus main body 101 in which various devices for image formation such as a photoconductive drum and a developing device are mounted, and a document reader 102 attached displaceably relative to an opening in an upper surface of the apparatus main body 101 between a closing posture S1 (see FIG. 7A) and an opening posture S2 (see FIG. 7B) by rotating about a transversely extending supporting shaft 103.
The document reader 102 is a heavy article internally provided with an unillustrated contact glass which a document surface faces, an unillustrated light source for emitting a light to the document surface, a plurality of unillustrated mirrors for introducing a reflected light from the document surface to a CCD, and an unillustrated moving mechanism for moving the light source and the mirrors. Such a document reader 102 is made openable and closable so that the interior of the apparatus main body 101 can be inspected by opening the document reader 102 and unillustrated developing devices are detached and attached for replacement.
A pair of left and right coupling arms 104 are disposed between the apparatus main body 101 and the document reader 102. A bottom end portion of each coupling arm 104 is supported rotatably about a transversely extending supporting shaft 104a, whereas an upper end portion 104b thereof is movable along a corresponding guiding groove 105 formed in a bottom surface of the document reader 102 while being so guided as not to come out. Accordingly, the respective coupling arms 104 turn about the supporting shafts 104a and the upper end portions 104b thereof are moved back and forth along the corresponding guiding grooves 105 by opening and closing the document reader 102.
A pair of left and right stoppers 106 are provided to keep the document reader 102 in the opening posture S2. When the upper end portions 104b of the coupling arms 104 are moved from the front end portions of the guiding grooves 105 and passed the stoppers 106 to set the document reader 102 in the opening posture S2, their upper end portions 104b are stopped by these stoppers 106 as shown in FIG. 7B. The coupling arms 104 are prevented from turning in clockwise direction about the supporting shafts 104a by the stoppers 106, whereby the document reader 102 can be kept in the opening posture S2.
The stoppers 106 are supported rotatably about vertical shafts 106a provided at specified positions inward of the coupling arms 104 on the bottom surface of the document reader 102. When the coupling arms 104 pass the stoppers 106 to set the document reader 102 in the opening posture S2, the stoppers 106 come to rest on protuberances 106b projecting from the bottom surface of the document reader 102 to be stopped. Accordingly, the stoppers 106 do not rotate even if the upper end portions 104b of the coupling arms 104 push the stoppers 106 forward. Thus, the document reader 102 can be kept in the opening posture S2.
An operating lever 107 for rotating such stoppers 106 toward the corresponding coupling arms 104 about the vertical shafts 106a is provided at the front side of the document reader 102. If this operating lever 107 is operated, for example, to right, the outer ends of the respective stoppers 106 are rotated toward the coupling arms 104 about the vertical shafts 106a. Then, the stoppers 106 are moved to such positions (retracted positions) as not to be interfered with by the coupling arms 104 after temporarily pushing the coupling arms 104 backward as shown in FIG. 7C.
The pair of coupling arms 104 are made rotatable in clockwise direction about the supporting shafts 104a by operating the operating lever 107 to move the stoppers 106 to the retracted positions. Thus, the document reader 102 can be displaced from the opening posture S2 to the closing posture S1 shown in FIG. 7A.
Japanese Unexamined Patent Publication No. 2005-62326 discloses an image forming apparatus provided with an apparatus main body constructed to enable an image forming operation, and a document reader attached openably and closably relative to the apparatus main body. However, this publication discloses nothing corresponding to the above stoppers.
In the image forming apparatus 100 shown in FIGS. 7A to 7C, upon returning the document reader 102 set in the opening posture S2 to the closing posture S1, the stoppers 106 have to be rotated in clockwise and counterclockwise directions about the vertical shafts 106a by operating the operating lever 107, the oblique coupling arms 104 have to be pushed in a direction toward their upright positions, and the document reader 102 has to be temporarily lifted up via the coupling arms 104.
However, it is quite difficult to lift the heavy document reader 102 only by operating the operating lever 107. Accordingly, upon closing the document reader 102, a user has been performing a cumbersome operation of moving the operating lever 107 by one hand while lifting a front end of the document reader 102 by the other hand.